spector you're pretty much spot on with everything but it's also important to mention that low rep strength usually does little for muscular development.
"The fact is that it isn't just the muscles that make you strong, it's also how the nervous system controls those muscles and your natural birth-given leverages.
Muscles adapt differently to different loading schemes. If you perpetually do low reps, train to improve neuromuscular coordination and perfect lifting technique, then you will likely gain strength faster than muscle size. That type of training is designed to preferentially increase maximum strength. However, if you train with higher reps and a higher total volume (as determined by weights x reps x sets) then you will be training to increase muscle mass because that is the adaptive response the body has to such training. Of course you will get stronger as well, because a bigger muscle is a stronger muscle, but also because of neuromuscular adaptations to a degree.
So, essentially, strength is composed of two trainable components - the muscles' capacity to generate force and the nervous system's ability to efficiently recruit the motor units of those muscles to lift weights. You can train each aspect individually to degree, but you can never completely separate the two. Strength athletes cannot lift maximal weights unless they have both of these qualities in sufficient quantities - strength is the product of both.
Bodybuilders focus on the first quality - muscular capacity. It also happens that the biggest muscles are created not only by increasing absolute strength but also by increasing endurance in roughly the 5 to 15 rep range. So bodybuilding training is, in essence, strength-endurance training. But make no mistake, aside from the large increase in neuromuscular coordination that all beginners experience and the small continuing "improvements" that occur from there, the only way to continue to significantly increase strength-endurance - in other words the ability to lift weights for reps - is for the muscles to get bigger. It is a simple physiological fact that cannot be disputed. If you will notice, in my previous responses I was always careful to say that trainees must increase their "strength for reps", not simply their strength or their one-rep maximums. This is why." - casey butt